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I always advise my customers to use “native” plants in their landscapes.  Nothing makes me crazier than when a customer wants to use some palm tree native to Borneo in their landscape here in DC, MD or VA.  Although I’m writing with my horticulture hat on right now (versus my turfgrass hat), this concept goes back to what I’ve said all along.  You must choose the correct type or species of turfgrass based on the region in which you live.  But, with larger shrubs and trees, that gets a little more complex.  If you want mission success in your landscape, you need to know a little bit about where you live – what are the conditions; the soil, the amount of sun, the weather, moisture…all sorts of considerations.


In Virginia, we make it easy.  You live in one of three regions – the coastal plain, the Piedmont or the mountains.  Each one of these areas has specific considerations and therefore has specific plants that will do well in each of those regions.


Why use native plants?  What’s the big deal?  Well, in this blog post I’m going to discuss some of the issues surrounding native, alien and invasive plants.


Native type plants have evolved within a specific area and are dispersed throughout that area without human intervention.  They could be called “indigenous” to a geographic area.  Native plants form the primary component of the living landscape and provide food and shelter for native animal species.  Native plants co-evolved with native animals over many thousands to millions of years and have formed complex and interdependent relationships.  Our native fauna depend on native flora to provide food and cover.  Many animals require specific plants for their survival.


How long must a plant species be located in an area in order for us to consider it native to that place - two hundred years, since colonization, since before agriculture began?  For example, for those who consider two hundred years sufficient, Queen Anne's lace would be native - yet we know from historical records that this plant has a European origin.  We usually depend on local plants, the uncultivated plant life of a given region, to tell us which plants are native.  However, these inventories are sometimes inconsistent and are subject to repeated debate.  I guess only fossil records can really prove that a plant evolved in a particular place, but even fossils can be misinterpreted.


If we randomly pick a spot in time and say "plants here before this date are native," we may not be acknowledging that for centuries, indigenous peoples, traders, explorers, and botanists have had an impact on local floras with their activities.  Geopolitical and environmental boundaries also play a role in defining native plants.  To say a plant is "native to North America" or "native to Virginia" implies that it is suitable for growth throughout North America or Virginia, when in fact it may only occur naturally in limited microclimates or sections and thus only be suitable for growth in equally limited scenery situations. 


Using native plants in your landscape means using plants that are better suited for that region.  Native plants use less water, require less fertilizer and less pesticides.  As I alluded to earlier, native plants also increase the presence of desirable wildlife.


Ecotypes (sometimes called ecospecies) describe a genetically distinct geographic variety, population or race within a species, which is adapted to specific environmental conditions.  Typically, ecotypes exhibit phenotypic differences (such as in morphology or physiology) stemming from environmental heterogeneity and are capable of inter-breeding with other geographically adjacent ecotypes without loss of fertility or vigor.  Basically, ecotypes are the same species that are found in different habitats and have evolved specific adaptations to their differing environments – taxonomically equivalent to a “sub-species”.  Red maple, for example, is native from Florida to Canada, but some sub-species have adapted to dry or wet sites, cold or warm climates.  Although technically red maple is native to a large section of North America, one ecotype will not necessarily perform successfully in another site because it is not adapted to the site's conditions.  The larger the geographic range of the species, the more occasion there is for dissimilarity.  


Exotic plants, also known as non-native, introduced, “non-indigenous” or alien plants, are species that occur in cultivation or in the wild.  These plants may have been transported across boundaries by people and their activities.  Sometimes they are species introduced intentionally or accidentally, into a new region by humans.  Over time, many flora and animals have expanded their ranges slowly and without human assistance.  As people began cultivating plants, they brought beneficial and favored species along when they moved into new regions or traded with people in distant lands.  Humans became a new pathway, enabling many species to move into new locations.


According to The Flora of North America, one-fifth to one-third of the plant species encountered north of Mexico had their beginning in other continents.  Several exotic plant introductions, such as lily-of-the-valley, day lilies, and daffodils, have become naturalized, meaning that they have succeeded in reproducing and spreading to a restricted extent on their own.  Unlike invasive plants, most naturalized plants are not a severe threat to other species or to an ecosystem.  In fact, the ability to naturalize is often considered an advantageous feature in horticulture.  Wildflowers can be true natives or introduced plants that have been naturalized for over two hundred years.


A small percentage of naturalized exotic plants become invasive.  Invasive plants are those that reproduce quickly, displace many of the other species in their domain, and are difficult to eradicate.  Invasive plants are species that cause health, economic or ecological damage in their new range.  More than 30,000 species of plants have been introduced to the United States since the time of Christopher Columbus.  Most were introduced intentionally, and many provide great benefits to society as agricultural crops and landscape ornamentals.  Some were introduced accidentally, for example, in ship ballast, in packing material and as seed contaminants.  Of these introduced species, fewer than 3,000 have naturalized and become established in the United States outside cultivation.  Of the 3,500 plant species in Virginia, more than 800 have been introduced since the founding of Jamestown.  The Virginia Department of Conservation and Recreation currently lists more than 100 of these species as invasive.  In the United States, invasive species cause an estimated $120 billion in annual economic losses, including costs to manage their effects.  Annual costs and damages arising from invasive plants alone are estimated at $34 billion.  Purple loosestrife in the northern US and kudzu in the southern states are classic examples of invasive plants that profoundly affect the landscape.  In Fairfax County Virginia, bamboo is an extremely damaging and problematic invasive plant.  Invasiveness can range from the minor nuisance of garden plants, such as Lamb's ears, that tend to edge out their neighbors, to the other end of the spectrum, where the melaleuca tree from Australia is literally drying out Florida's marshes to meet its high water requirements.  Melaleuca is an example of an exotic species that is considered a serious invader because it enters disturbed lands, colonizes them and changes the ecology of them in detrimental ways.


One of the main reasons people promote native plants is to avoid the devastation that invasive plants may bring on landscapes and forests.  Exotic introductions that do become invasive, like kudzu, multi flora rose, and honeysuckle are a costly menace nearly impossible to control, much less eradicate.  Why do a small percentage of plants exhibit invasive tendencies, while the majority of plant introductions are benign or beneficial?  The answer lies in the combination of two factors: traits that invasive plant species share and traits of the site that make it susceptible to invasion.  No plant is inherently invasive under all circumstances.  Although more often it is exotic introductions that invade, native plants can also become invasive pests.  Native grape vines like fox grape form suffocating thickets over shrubs and rapidly climb trees, threatening to out-compete their hosts for light.  Though native to eastern and central North America, wild grape is an indisputable pest.  Other native plants that are often invasive include blackberries, poison ivy, wild onions and cattails.  Just as with exotic introductions, it is a small percentage of native species that cause problems.


Native plants have an important role to play in modern landscaping.  Arguments that are made in favor of native plants include lower maintenance, regional uniqueness, biological diversity, and wildlife habitat.  One theory holds that native plants are easier to care for because they have evolved in a place over many years, developing resistance to climatic extremes, insect feeding, disease pathogens and other stresses of the local environment for which non-native plants may not be prepared.  This may be true in some cases; however, it is important to note that native plants placed under stressful conditions fare no better than exotic ones if the plant is not carefully matched to the site.  Some exotic plants actually perform better and require less maintenance because of the qualities they were selected for, and because their insect predators and disease pathogens are frequently not imported with them. 


Another factor to consider is the interaction of native plants with the “built up”, urban or suburban non-native environment.  In an urban setting, for example, there is no planting site that approximates what would have been there prior to urbanization.  The original landscape in both cities and suburbs often has been changed so completely that the microclimate, soil type, soil hydrology, and insect populations no longer are what they were when the native plants of the area evolved.  To put a native tree, for example, in a median strip planting on a downtown street because it is native to the surrounding countryside would be foolish unless the tree is known to tolerate the heat of the asphalt, car exhaust, salt from the snowplows, a limited root zone, intermittent flooding, and periodic drought.


If native plants are used simply because they are native, without proper regard to site conditions, the results may be insufficient.  The most critical issue is not native plants versus exotic plants - it is appropriate versus inappropriate plant selection, given the constraints and opportunities of the site.  The more closely a plant's characteristics match the site's characteristics, the better chance for the plant’s survival and vigor.  If a native plant meets those requirements, by all means use that plant.


While we can and should strive to use plants long found in our region, perhaps the term native plants should be used with some modesty.  Using diverse plantings will create beauty and prevent the susceptibility to disease that can come from large scale single-species plantings, avoiding disasters such as that of the American elm in the mid-twentieth century.


In the quest for a diverse, healthy landscape, which may be a mix of native and exotic species, references are available both to help find the right plant and to avoid the trouble makers.  A little research before selecting plants can save time, money, and aggravation.  Or, you can consult with someone like me.  Reference guides may warn that a plant is invasive under certain circumstances, but they may not, and nursery catalogs frequently won't.  Phrases like "a very vigorous grower" can be euphemisms for potential invasiveness.  Don’t be fooled.  Treat such phrases as red flags.  Be sure to look in more than one plant reference to gather more than one perspective on any species you have in mind, especially if you suspect it may be invasive.  After invasive potential is ruled out, the physical limitations and possibilities of the site should be the first and most important consideration in the exciting process of selecting new plants for our landscapes.

In the early spring here in the mid-Atlantic region, I started to see some common weed activity.  What is very visible this time of year is wild onion and wild garlic.  Wild garlic (Allium vineale) and wild onion (Allium canadense) are winter perennials.  They emerge in late fall from underground bulbs and grow through the winter and spring.  In late spring, aerial bulblets are formed and the plants die back in early summer.  The underground bulbs can persist in the soil for several years.  While both have thin, green, waxy leaves, those of wild garlic are round and hollow, while those of wild onion are flat and solid.  Oddly enough, the garlic smells like onion and vice versa.


Mowing will not kill wild garlic or wild onion.  However regular mowing can weaken the plants and prevent them from setting seed.


Unfortunately, there are no pre-emergent herbicides that will control wild onion or wild garlic.  They must be treated with post-emergent herbicides.  Perseverance is the key.  These plants will need to be sprayed more than once and for more than one season.  One trait that makes control difficult is that both have a slender, shiny leaf to which herbicides don't readily adhere.  Unlike most weeds, mowing wild garlic or wild onion immediately before applying an herbicide may improve uptake.  After application, do not mow for at least two weeks.


Treat wild garlic and wild onion in November and again in late winter or early spring (February or early March) before these plants can produce the next generation of bulbs.  However, be careful not to apply most weed killers onto Centipedegrass or St. Augustinegrass during their spring “green up” period.  Inspect the lawn again in the spring and the next fall, and treat if necessary.


Imazaquin, the active ingredient in Image Nutsedge Killer, will provide control for wild garlic and wild onion.  N.B - This product should not be used on fescue and should not be applied to warm season turf during green up in spring.  Wait at least 1 & 1/2 months after treatment before reseeding, winter overseeding or plugging lawns.  This product is not for use on newly planted lawns, nor on winter over-seeded lawns with annual ryegrass.


Three-way broadleaf herbicides containing 2,4-D, dicamba and mecoprop (look for any or two or all three in a spray) will provide control of wild garlic and wild onion with repeat applications. Examples of these products are Bayer Advanced Southern Weed Killer for Lawns, Spectracide Weed Stop for Lawns – for Southern Lawns, Lilly Miller Lawn Weed Killer, Southern Ag Lawn Weed Killer with Trimec, and Ferti-lome Weed-Out Lawn Weed Killer.  These products can be used safely on most turfgrasses, but reduced rates are recommended when applying to St. Augustinegrass or Centipedegrass.  Apply during November, very early spring, and again the next November for best control.  N.B. - Do not apply these herbicides during the spring green up of warm season turfgrasses, or over the root zone of nearby ornamental trees and shrubs.  Do not apply these products to newly seeded grasses until well established (after the third mowing).  Treated areas may be reseeded three to four weeks after application.  Always check the product label for rate of application and to determine that it is safe for use on your species of turfgrass.


Metsulfuron (such as Manor and Blade) is an herbicide which is packaged for landscape professionals and gives very good control of wild onion and garlic.  Due to the cost of these selective herbicides, it may be more economical to hire a landscape professional for weed treatment.  Metsulfuron can be used on Bermudagrass, St. Augustinegrass, Centipedegrass, and Zoysiagrass.  


The addition of a non-ionic surfactant (such as Southern Ag Surfactant for Herbicides) may be a good idea too.  It is required at 2 teaspoons per gallon of spray mix for best control.  Read my blog post on "Wetting Agents".  A non-ionic surfactant will help the herbicide adhere to the leaves for increased penetration.  Do not apply Metsulfuron to a lawn if over-seeded with annual ryegrass or over-seed for 8 weeks after application.  Do not plant woody ornamentals in treated areas for one year after application of Metsulfuron.  Do not apply Metsulfuron herbicides within two times the width of the drip line of desirable hardwood trees.


Glyphosate, the nonselective herbicide found in Roundup Original, Eraser Systemic Weed & Grass Killer, Quick Kill Grass & Weed Killer, Bonide Kleenup Grass & Weed Killer, Hi-Yield Super Concentrate Killzall Weed & Grass, Maxide Super Concentrate 41% Weed & Grass Killer, and Southern States Grass & Weed Killer Concentrate, will also provide control of wild garlic and wild onion.  If you are unable to prevent glyphosate from getting on desired actively growing grasses, a selective herbicide should be used.  To do the least damage to your turfgrass, apply glyphosate only to warm season grasses during winter, when they are completely dormant.  However, during mild winters, the turfgrass may not be completely dormant.  I recommend not messing with a non-selective herbicide like glyphosate.


One answer to these weeds in flower beds and high-quality lawns is some smart pulling.  Sometimes they are tough to pull.  The entire clump should come out easily when pulled gently but firmly after a good, soaking rain.  This is one of the many benefits of improving your soil — weeds that sprout out of nice, loose, rich soil that contains a lot of organic matter practically pull themselves out. Conversely, weeds that grow in lousy, compacted clay are usually firmly anchored.

Pulling from wet soil is always more productive than pulling from dry soil.  So go out after a rain, reach down to the soil line and tug gently; that's how you get the underground bulb out completely.  If you only snap them off at the soil line, the plant is not harmed; you spend the same amount of time and energy as someone who does it correctly, but get no benefit.  Personally, I have about a 50% success rate each time I go after these weeds by pulling them in wet soil.  But, over time, they will be eradicated.

You can also remove tight clumps with a sharp, long-handled “poachers spade”, which is also a very useful tool for transplanting bulbs, plants and rabbit hunting in Merry Old England.

Single sprouts are the most annoying and time-consuming to deal with.  If you have a large area with mostly single plants, clear small sections at a time, being sure to pull slowly and get the bulbs completely out.  Start with highly visible areas and give yourself several seasons to do it all; if you've been cursing them for the past five years, you can't expect overnight eradication.  And don't let the un-pulled plants in other areas set seed while you're doing this; mow or weed-whack the tops off those miscreants before they can procreate.


I really don’t see wild onion and wild garlic as a great threat to the safety and security of your turfgrass.  I mean, it can get out of control.  Just like everything else, if you stay on top of it, little by little, it will go away.  You know how I am about consistency.  These weeds do violate my consistency standards.  And, you have to be careful about any applications.  See where I underlined a couple things.  Stick to it and you will be victorious.

In this blog post, I will be discussing SOD.  Sod is a good thing.  It is turfgrass that has already germinated and is growing, like a living carpet.  And it already includes a layer of some decent topsoil.  For the most part, it is some mature turfgrass plants that have been professionally grown.  It is usually harvested into slabs, then the slabs are rolled up.  If done correctly, it can be a readymade lawn.  If done incorrectly, it can be a huge waste of time, money and other resources.  As usual, my blog post here is geared toward the “do-it-yourself” turfgrass warrior.  Many sod farms will do delivery, site preparation and installation.  Sometimes, that’s the bulk of the cost…not just the price of the sod.  But, if you did well on your last physical fitness test, installing sod will be no big deal.


I have not yet had a customer who has installed a complete yard or lawn of sod.  But, I do use sod quite a bit for repair, filling bare spots, etc.  In some cases, areas where I’ve used sod have been quite large.  I’ve also used sod in areas where there was an infestation of some sort.  Of course, in that area, before any preparation, one must kill or mitigate whatever the problem was in that area.  For example, if you have an area in your cool season turf infested by Bermudagrass or Poa Annua, all that stuff has to be decisively engaged with an herbicide before you start site preparation, much less installation.  Old, dead sod needs to be removed or tilled into the soil.  I’ll get into that.  Let’s say for argument’s sake, in the case of this blog post, that there are no real serious problems and you are just sodding an area because you feel like it.


A Few Words About Sod


Sodding provides many advantages over seeding:


§ Creates an instant green lawn or recreational surface.


§ Gives immediate erosion control.


§ Eliminates dust and mud.


§ Eliminates weed control during establishment.


§ Can be used quickly.


§ Can be established almost year round.


§ Can get the best turfgrass varieties from producers.


§ Can be used for total installation or repair of smaller areas.


Selecting the Type of Turfgrass


This goes back to my earlier blog posts on turfgrass selection.  A quality lawn results from using the right grass species and/or variety, proper planting and establishment, and sound management.  Planting the right turfgrass for your site reduces the need for pesticides and other amendments.  This goes for any method of establishment – sodding, seeding, sprigging, etc.  The most important step for the Turfgrass Warrior is selecting the proper turfgrass for the environment.  Turfgrasses are perennial, so turfgrasses are expected to live indefinitely with proper management.  Because of this, choose cautiously from among the various species and varieties.  Turfgrasses that provide winter lawn color in most areas of mid Atlantic are known as cool-season grasses.  Grasses which go dormant after the first hard frost, and stay brown through the winter months are known as warm-season grasses.  The warm season grasses generally need less maintenance as their water requirements are lower, and their shorter growing season requires less mowing per year.  Turfgrass species will not perform equally in the different climate, soils, and management programs that are found in the mid Atlantic region.


What type of sod do you need?


Most types of sod being grown in the mid Atlantic are Kentucky bluegrass blends, tall fescue or tall fescue-Kentucky bluegrass mixtures, Bermudagrass, and zoysiagrass.  Each type is best suited to particular uses and geographic areas in mid Atlantic. 


Most states in the US have their own organizations that “certify” turfgrass (and sometimes crop) seed.  At the national level, we have The National Turfgrass EvaluationProgram (NTEP).  NTEP has expanded to the evaluation of seventeen turfgrass species in as many as forty U.S. states and six provinces in Canada.  Information such as turfgrass quality, color, density, resistance to diseases and insects, tolerance to heat, cold, drought and traffic is collected and summarized by NTEP annually.   In Maryland, it is the state Department of Agriculture that certifies seed. 


Sod in Virginia is grown in the Virginia Crop Improvement Association (VCIA) sod certification program.  This sod must meet established standards of quality, which also qualifies the sod to be marketed under the Virginia Department of Agriculture’s "Virginia's Finest" program.  VCIA certified sod or "Virginia's Finest" is sod of high quality, meeting rigid standards requiring pre-planting field inspections, prescribed varieties and mixtures, periodic production inspections, and a final pre-harvest inspection.  Quality sod contains excellent turf varieties with good sod strength and has no serious insect, weed, or disease problems.


Before Contacting Growers


What’s the first thing you need to do before you do anything in your lawn or landscape?  You should have a soil sample taken.  Give me a call.  Get that done at least one month prior to preparing the soil so you can follow the lime, sulfur or fertilizer recommendations prior to sod installation. 


Measure the area to be sodded in square yards or square feet.  Sod isn’t cheap.  Don’t get more than you need.  Here’s some conversions:


1 square yard = 9 square ft.

111.1 sq. yds. = 1,000 sq. ft.

1 acre = 43,560 sq. ft.

1 acre = 4,840 sq. yds.


With regard to safety, make sure you have the proper vehicle to transport the amount of sod you need and how many trips you will need to make.  The safe carrying capacity of vehicles varies (in square yards):


Medium Size Car: 5 to 10


Half Ton Pickup: 25 to 50


One Ton Truck: 150 to 200


Two Ton truck: 300 to 350


Tandem (10 Wheel): 500 to 600


Tractor Trailer (18 Wheel): 1,000 to 1,100


If the sod is wet, it is real heavy.  Less sod can be carried when it is wet.  Dry sod weighs about 20 to 25 lbs. per square yard whereas wet sod can weigh 30 to 40 lbs. per square yard.  A pallet of sod will contain 50 to 75 square yards (450 to 675 sq. ft.) of sod.


When Contacting Growers


You need to know how many square yards or square feet of the particular type of sod you want to purchase.  Remember that some sod comes with netting to aid in harvest.  I hate that stuff.  If you ever have to work that area again, that netting is terrible.  Asking about netted sod is an important question.  Netted sod may not be desirable if you anticipate cleated traffic on the sodded area (e.g. athletic fields).  Determine what services each grower you contact can provide and the cost of those services (e.g. pallet charges).  Sod-farm services vary and can include any of the following:


  • Cut your own sod, generally sold by the acre.

  • Pick up sod on pallet at farm.

  • Delivery to site.

  • Site grading, fertilization, installation.

  • Post-installation lawn service programs.


Once you select a grower, call as far ahead of installation time as possible to ensure the sod will be available when you need it.  And, you want to make sure that the sod was harvested just prior to installation.  Get fresh sod.


Site Preparation


There are no shortcuts to soil preparation when sodding.  Normally, site preparation for sod is almost identical to preparation for seeding to ensure transplanting success.  Remove existing grass and/or till the soil down to a four inch depth.  Allow time for the soil to settle and then establish the final grade.  To greatly improve the chances for long-term success, incorporate fertilizer and lime/sulfur according to the soil test/lab recommendations.  Rake the area until smooth and be sure to remove stones and other debris.


When the Sod is Ready for Pickup or Delivery


Prepare the site for installation prior to pick-up or delivery.  If the soil at the installation site is extremely dry, lightly water it 12 hours prior to installation.  Sod is perishable and should be installed within eight hours of harvest!  Wear work clothes you don’t mind getting real dirty.  If you are buying sod by the roll and are concerned about keeping your vehicle clean, bring something on which to lay the sod.  Do not overload your vehicle.  On hot days, when sod will be transported for an hour or more use light, vented covers to reduce drying and heat buildup.  If buying VCIA Certified Sod, request the certification labels with each load you purchase.  In fact, if you buy sod from anywhere, see if they have the certification labels.  That’ll teach ‘em you mean business!


Installing Your Sod


Lightly rake the area to be sodded just prior to installation.  Sod survival is greatest when installed on relatively loose and moist soil that is cool.  Do not install sod on grass, debris, or rocks.  Lay the first line of sod along a straight line such as a driveway, sidewalk, or use a string stretched between two stakes.  Then stagger the sod pieces in the adjacent rows in a "brickwork" fashion.  Since sod pieces may shrink after installation, push the sod pieces together tightly.  Try to minimize soil compaction in the installation area by using wheel barrows to move the sod.  Plywood boards laid in heavy tracking areas will minimize compaction.  Roll the sod with a heavy hand roller after you lay it to press roots to the soil.  Saturate the sod with water immediately after installation, wetting the soil under the sod to a four inch depth.  Examine the soil under several pieces of sod to ensure proper wetting.  You might need to water it as deep as 6 to 8 inches.


Maintaining Your Sod


Begin mowing the sod with sharp blades as soon as it is rooted.  That might take a couple months.  Mow frequently enough so that you never remove more than one-third of the existing green tissue.  Mow it high.  Mow Kentucky bluegrass and tall Fescue sods at least two to two and one-half inches and Bermudagrass and Zoysia at one-half to one inch.  From October through April, apply water every second or third day for three weeks, even if it rains. The rule is to make sure the soil is wet to a three to four inch depth.  In hot weather (above 80 degrees F) water the sod daily, wetting the soil thoroughly until the sod is well rooted.  After the sod is well rooted, irrigate to prevent drought damage.


Sod can be installed almost anytime of the year.  The best time to lay sod, however, is in late summer and early fall when temperatures are cooler but grass continues to grow.  Spring is the second best time to lay sod and is the preferable time for warm-season grasses such as centipede, zoysia, Bermuda, and St. Augustine that become dormant in the winter.  Avoid installing sod in summer as the extra water required for establishment could result in blight and disease.


Sod can be a super resource.  But, you shouldn’t just throw it down and expect it to be beautiful.  Just like anything else, if you just throw it down, it will probably look like you just threw it down.  You don’t want mission failure in this type of operation.  You need to PLAN, PREPARE then EXECUTE.  If you do that, it will pay off in the long run.

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